Merge "Split the header into a separate file."

26 files changed, 155 insertions, 121 deletions

diff --git a/java/src/com/android/inputmethod/latin/makedict/AbstractDictDecoder.java b/java/src/com/android/inputmethod/latin/makedict/AbstractDictDecoder.java
index b75fc37d9..bbbb8e461 100644
--- a/java/src/com/android/inputmethod/latin/makedict/AbstractDictDecoder.java
+++ b/java/src/com/android/inputmethod/latin/makedict/AbstractDictDecoder.java
@@ -36,27 +36,25 @@ public abstract class AbstractDictDecoder implements DictDecoder {
     private static final int ERROR_CANNOT_READ = 1;
     private static final int ERROR_WRONG_FORMAT = 2;
 
-    protected FileHeader readHeader(final DictBuffer dictBuffer)
+    protected FileHeader readHeader(final DictBuffer headerBuffer)
             throws IOException, UnsupportedFormatException {
-        if (dictBuffer == null) {
+        if (headerBuffer == null) {
             openDictBuffer();
         }
 
-        final int version = HeaderReader.readVersion(dictBuffer);
+        final int version = HeaderReader.readVersion(headerBuffer);
         if (version < FormatSpec.MINIMUM_SUPPORTED_VERSION
                 || version > FormatSpec.MAXIMUM_SUPPORTED_VERSION) {
           throw new UnsupportedFormatException("Unsupported version : " + version);
         }
         // TODO: Remove this field.
-        final int optionsFlags = HeaderReader.readOptionFlags(dictBuffer);
-
-        final int headerSize = HeaderReader.readHeaderSize(dictBuffer);
-
+        final int optionsFlags = HeaderReader.readOptionFlags(headerBuffer);
+        final int headerSize = HeaderReader.readHeaderSize(headerBuffer);
         if (headerSize < 0) {
             throw new UnsupportedFormatException("header size can't be negative.");
         }
 
-        final HashMap<String, String> attributes = HeaderReader.readAttributes(dictBuffer,
+        final HashMap<String, String> attributes = HeaderReader.readAttributes(headerBuffer,
                 headerSize);
 
         final FileHeader header = new FileHeader(headerSize,
diff --git a/java/src/com/android/inputmethod/latin/makedict/BinaryDictDecoderUtils.java b/java/src/com/android/inputmethod/latin/makedict/BinaryDictDecoderUtils.java
index 17c609fbe..83ee7d685 100644
--- a/java/src/com/android/inputmethod/latin/makedict/BinaryDictDecoderUtils.java
+++ b/java/src/com/android/inputmethod/latin/makedict/BinaryDictDecoderUtils.java
@@ -600,7 +600,7 @@ public final class BinaryDictDecoderUtils {
 
         Map<Integer, PtNodeArray> reverseNodeArrayMapping = new TreeMap<Integer, PtNodeArray>();
         Map<Integer, PtNode> reversePtNodeMapping = new TreeMap<Integer, PtNode>();
-        final PtNodeArray root = readNodeArray(dictDecoder, fileHeader.mHeaderSize,
+        final PtNodeArray root = readNodeArray(dictDecoder, fileHeader.mBodyOffset,
                 reverseNodeArrayMapping, reversePtNodeMapping, fileHeader.mFormatOptions);
 
         FusionDictionary newDict = new FusionDictionary(root, fileHeader.mDictionaryOptions);
diff --git a/java/src/com/android/inputmethod/latin/makedict/BinaryDictIOUtils.java b/java/src/com/android/inputmethod/latin/makedict/BinaryDictIOUtils.java
index 62d9ad86d..86ebf5844 100644
--- a/java/src/com/android/inputmethod/latin/makedict/BinaryDictIOUtils.java
+++ b/java/src/com/android/inputmethod/latin/makedict/BinaryDictIOUtils.java
@@ -62,7 +62,7 @@ public final class BinaryDictIOUtils {
      * Retrieves all node arrays without recursive call.
      */
     private static void readUnigramsAndBigramsBinaryInner(final DictDecoder dictDecoder,
-            final int headerSize, final Map<Integer, String> words,
+            final int bodyOffset, final Map<Integer, String> words,
             final Map<Integer, Integer> frequencies,
             final Map<Integer, ArrayList<PendingAttribute>> bigrams,
             final FormatOptions formatOptions) {
@@ -71,7 +71,7 @@ public final class BinaryDictIOUtils {
         Stack<Position> stack = new Stack<Position>();
         int index = 0;
 
-        Position initPos = new Position(headerSize, 0);
+        Position initPos = new Position(bodyOffset, 0);
         stack.push(initPos);
 
         while (!stack.empty()) {
@@ -154,7 +154,7 @@ public final class BinaryDictIOUtils {
             UnsupportedFormatException {
         // Read header
         final FileHeader header = dictDecoder.readHeader();
-        readUnigramsAndBigramsBinaryInner(dictDecoder, header.mHeaderSize, words,
+        readUnigramsAndBigramsBinaryInner(dictDecoder, header.mBodyOffset, words,
                 frequencies, bigrams, header.mFormatOptions);
     }
 
diff --git a/java/src/com/android/inputmethod/latin/makedict/FormatSpec.java b/java/src/com/android/inputmethod/latin/makedict/FormatSpec.java
index b81c8d8e5..846aacf11 100644
--- a/java/src/com/android/inputmethod/latin/makedict/FormatSpec.java
+++ b/java/src/com/android/inputmethod/latin/makedict/FormatSpec.java
@@ -199,13 +199,19 @@ public final class FormatSpec {
      */
 
     public static final int MAGIC_NUMBER = 0x9BC13AFE;
-    static final int MINIMUM_SUPPORTED_VERSION = 2;
-    static final int MAXIMUM_SUPPORTED_VERSION = 4;
     static final int NOT_A_VERSION_NUMBER = -1;
     static final int FIRST_VERSION_WITH_DYNAMIC_UPDATE = 3;
     static final int FIRST_VERSION_WITH_TERMINAL_ID = 4;
+
+    // These MUST have the same values as the relevant constants in format_utils.h.
+    // From version 4 on, we use version * 100 + revision as a version number. That allows
+    // us to change the format during development while having testing devices remove
+    // older files with each upgrade, while still having a readable versioning scheme.
+    public static final int VERSION2 = 2;
     public static final int VERSION3 = 3;
-    public static final int VERSION4 = 4;
+    public static final int VERSION4 = 400;
+    static final int MINIMUM_SUPPORTED_VERSION = VERSION2;
+    static final int MAXIMUM_SUPPORTED_VERSION = VERSION4;
 
     // These options need to be the same numeric values as the one in the native reading code.
     static final int GERMAN_UMLAUT_PROCESSING_FLAG = 0x1;
@@ -263,8 +269,10 @@ public final class FormatSpec {
     static final int PTNODE_ATTRIBUTE_MAX_ADDRESS_SIZE = 3;
     static final int PTNODE_SHORTCUT_LIST_SIZE_SIZE = 2;
 
-    // These values are used only by version 4 or later.
-    public static final String TRIE_FILE_EXTENSION = ".trie";
+    // These values are used only by version 4 or later. They MUST match the definitions in
+    // ver4_dict_constants.cpp.
+    static final String TRIE_FILE_EXTENSION = ".trie";
+    public static final String HEADER_FILE_EXTENSION = ".header";
     static final String FREQ_FILE_EXTENSION = ".freq";
     static final String UNIGRAM_TIMESTAMP_FILE_EXTENSION = ".timestamp";
     // tat = Terminal Address Table
@@ -361,7 +369,7 @@ public final class FormatSpec {
      * Class representing file header.
      */
     public static final class FileHeader {
-        public final int mHeaderSize;
+        public final int mBodyOffset;
         public final DictionaryOptions mDictionaryOptions;
         public final FormatOptions mFormatOptions;
         // Note that these are corresponding definitions in native code in latinime::HeaderPolicy
@@ -377,9 +385,9 @@ public final class FormatSpec {
         private static final String DICTIONARY_DESCRIPTION_ATTRIBUTE = "description";
         public FileHeader(final int headerSize, final DictionaryOptions dictionaryOptions,
                 final FormatOptions formatOptions) {
-            mHeaderSize = headerSize;
             mDictionaryOptions = dictionaryOptions;
             mFormatOptions = formatOptions;
+            mBodyOffset = formatOptions.mVersion < VERSION4 ? headerSize : 0;
             if (null == getLocaleString()) {
                 throw new RuntimeException("Cannot create a FileHeader without a locale");
             }
diff --git a/java/src/com/android/inputmethod/latin/makedict/Ver4DictDecoder.java b/java/src/com/android/inputmethod/latin/makedict/Ver4DictDecoder.java
index 2cbec7cec..07522b54b 100644
--- a/java/src/com/android/inputmethod/latin/makedict/Ver4DictDecoder.java
+++ b/java/src/com/android/inputmethod/latin/makedict/Ver4DictDecoder.java
@@ -45,10 +45,12 @@ public class Ver4DictDecoder extends AbstractDictDecoder {
     protected static final int FILETYPE_TERMINAL_ADDRESS_TABLE = 3;
     protected static final int FILETYPE_BIGRAM_FREQ = 4;
     protected static final int FILETYPE_SHORTCUT = 5;
+    protected static final int FILETYPE_HEADER = 6;
 
     protected final File mDictDirectory;
     protected final DictionaryBufferFactory mBufferFactory;
     protected DictBuffer mDictBuffer;
+    protected DictBuffer mHeaderBuffer;
     protected DictBuffer mFrequencyBuffer;
     protected DictBuffer mTerminalAddressTableBuffer;
     private BigramContentReader mBigramReader;
@@ -83,7 +85,7 @@ public class Ver4DictDecoder extends AbstractDictDecoder {
     @UsedForTesting
     /* package */ Ver4DictDecoder(final File dictDirectory, final int factoryFlag) {
         mDictDirectory = dictDirectory;
-        mDictBuffer = mFrequencyBuffer = null;
+        mDictBuffer = mHeaderBuffer = mFrequencyBuffer = null;
 
         if ((factoryFlag & MASK_DICTBUFFER) == USE_READONLY_BYTEBUFFER) {
             mBufferFactory = new DictionaryBufferFromReadOnlyByteBufferFactory();
@@ -100,13 +102,16 @@ public class Ver4DictDecoder extends AbstractDictDecoder {
     /* package */ Ver4DictDecoder(final File dictDirectory, final DictionaryBufferFactory factory) {
         mDictDirectory = dictDirectory;
         mBufferFactory = factory;
-        mDictBuffer = mFrequencyBuffer = null;
+        mDictBuffer = mHeaderBuffer = mFrequencyBuffer = null;
     }
 
     protected File getFile(final int fileType) throws UnsupportedFormatException {
         if (fileType == FILETYPE_TRIE) {
             return new File(mDictDirectory,
                     mDictDirectory.getName() + FormatSpec.TRIE_FILE_EXTENSION);
+        } else if (fileType == FILETYPE_HEADER) {
+            return new File(mDictDirectory,
+                    mDictDirectory.getName() + FormatSpec.HEADER_FILE_EXTENSION);
         } else if (fileType == FILETYPE_FREQUENCY) {
             return new File(mDictDirectory,
                     mDictDirectory.getName() + FormatSpec.FREQ_FILE_EXTENSION);
@@ -132,6 +137,7 @@ public class Ver4DictDecoder extends AbstractDictDecoder {
         if (!mDictDirectory.isDirectory()) {
             throw new UnsupportedFormatException("Format 4 dictionary needs a directory");
         }
+        mHeaderBuffer = mBufferFactory.getDictionaryBuffer(getFile(FILETYPE_HEADER));
         mDictBuffer = mBufferFactory.getDictionaryBuffer(getFile(FILETYPE_TRIE));
         mFrequencyBuffer = mBufferFactory.getDictionaryBuffer(getFile(FILETYPE_FREQUENCY));
         mTerminalAddressTableBuffer = mBufferFactory.getDictionaryBuffer(
@@ -150,16 +156,22 @@ public class Ver4DictDecoder extends AbstractDictDecoder {
     }
 
     @UsedForTesting
+    /* package */ DictBuffer getHeaderBuffer() {
+        return mHeaderBuffer;
+    }
+
+    @UsedForTesting
     /* package */ DictBuffer getDictBuffer() {
         return mDictBuffer;
     }
 
     @Override
     public FileHeader readHeader() throws IOException, UnsupportedFormatException {
-        if (mDictBuffer == null) {
+        if (mHeaderBuffer == null) {
             openDictBuffer();
         }
-        final FileHeader header = super.readHeader(mDictBuffer);
+        mHeaderBuffer.position(0);
+        final FileHeader header = super.readHeader(mHeaderBuffer);
         final int version = header.mFormatOptions.mVersion;
         if (version != FormatSpec.VERSION4) {
             throw new UnsupportedFormatException("File header has a wrong version : " + version);
diff --git a/java/src/com/android/inputmethod/latin/makedict/Ver4DictEncoder.java b/java/src/com/android/inputmethod/latin/makedict/Ver4DictEncoder.java
index 6d045c88a..1a245b6db 100644
--- a/java/src/com/android/inputmethod/latin/makedict/Ver4DictEncoder.java
+++ b/java/src/com/android/inputmethod/latin/makedict/Ver4DictEncoder.java
@@ -26,6 +26,7 @@ import com.android.inputmethod.latin.makedict.FusionDictionary.PtNode;
 import com.android.inputmethod.latin.makedict.FusionDictionary.PtNodeArray;
 import com.android.inputmethod.latin.makedict.FusionDictionary.WeightedString;
 import com.android.inputmethod.latin.utils.CollectionUtils;
+import com.android.inputmethod.latin.utils.FileUtils;
 
 import java.io.File;
 import java.io.FileNotFoundException;
@@ -45,8 +46,8 @@ public class Ver4DictEncoder implements DictEncoder {
     private final File mDictPlacedDir;
     private byte[] mTrieBuf;
     private int mTriePos;
-    private int mHeaderSize;
     private OutputStream mTrieOutStream;
+    private OutputStream mHeaderOutStream;
     private OutputStream mFreqOutStream;
     private OutputStream mUnigramTimestampOutStream;
     private OutputStream mTerminalAddressTableOutStream;
@@ -185,16 +186,21 @@ public class Ver4DictEncoder implements DictEncoder {
         mBaseFilename = header.getId() + "." + header.getVersion();
         mDictDir = new File(mDictPlacedDir, mBaseFilename);
         final File trieFile = new File(mDictDir, mBaseFilename + FormatSpec.TRIE_FILE_EXTENSION);
+        final File headerFile = new File(mDictDir,
+                mBaseFilename + FormatSpec.HEADER_FILE_EXTENSION);
         final File freqFile = new File(mDictDir, mBaseFilename + FormatSpec.FREQ_FILE_EXTENSION);
         final File timestampFile = new File(mDictDir,
                 mBaseFilename + FormatSpec.UNIGRAM_TIMESTAMP_FILE_EXTENSION);
         final File terminalAddressTableFile = new File(mDictDir,
                 mBaseFilename + FormatSpec.TERMINAL_ADDRESS_TABLE_FILE_EXTENSION);
         if (!mDictDir.isDirectory()) {
-            if (mDictDir.exists()) mDictDir.delete();
+            if (mDictDir.exists()) {
+                FileUtils.deleteRecursively(mDictDir);
+            }
             mDictDir.mkdirs();
         }
         mTrieOutStream = new FileOutputStream(trieFile);
+        mHeaderOutStream = new FileOutputStream(headerFile);
         mFreqOutStream = new FileOutputStream(freqFile);
         mTerminalAddressTableOutStream = new FileOutputStream(terminalAddressTableFile);
         if (formatOptions.mHasTimestamp) {
@@ -207,6 +213,9 @@ public class Ver4DictEncoder implements DictEncoder {
             if (mTrieOutStream != null) {
                 mTrieOutStream.close();
             }
+            if (mHeaderOutStream != null) {
+                mHeaderOutStream.close();
+            }
             if (mFreqOutStream != null) {
                 mFreqOutStream.close();
             }
@@ -218,6 +227,7 @@ public class Ver4DictEncoder implements DictEncoder {
             }
         } finally {
             mTrieOutStream = null;
+            mHeaderOutStream = null;
             mFreqOutStream = null;
             mTerminalAddressTableOutStream = null;
         }
@@ -238,8 +248,7 @@ public class Ver4DictEncoder implements DictEncoder {
             openStreams(formatOptions, dict.mOptions);
         }
 
-        mHeaderSize = BinaryDictEncoderUtils.writeDictionaryHeader(mTrieOutStream, dict,
-                formatOptions);
+        BinaryDictEncoderUtils.writeDictionaryHeader(mHeaderOutStream, dict, formatOptions);
 
         MakedictLog.i("Flattening the tree...");
         ArrayList<PtNodeArray> flatNodes = BinaryDictEncoderUtils.flattenTree(dict.mRootNodeArray);
@@ -423,7 +432,7 @@ public class Ver4DictEncoder implements DictEncoder {
                             ptNode.mFrequency, FormatSpec.FREQUENCY_AND_FLAGS_SIZE);
                     BinaryDictEncoderUtils.writeUIntToBuffer(terminalAddressTableBuf,
                             ptNode.mTerminalId * FormatSpec.TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE,
-                            ptNode.mCachedAddressAfterUpdate + mHeaderSize,
+                            ptNode.mCachedAddressAfterUpdate,
                             FormatSpec.TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE);
                 }
             }
diff --git a/java/src/com/android/inputmethod/latin/personalization/DecayingExpandableBinaryDictionaryBase.java b/java/src/com/android/inputmethod/latin/personalization/DecayingExpandableBinaryDictionaryBase.java
index f9733f725..02b09fb0c 100644
--- a/java/src/com/android/inputmethod/latin/personalization/DecayingExpandableBinaryDictionaryBase.java
+++ b/java/src/com/android/inputmethod/latin/personalization/DecayingExpandableBinaryDictionaryBase.java
@@ -122,7 +122,8 @@ public abstract class DecayingExpandableBinaryDictionaryBase extends ExpandableB
 
     @Override
     protected String getFileNameExtentionToOpenDict() {
-        return "/" + FormatSpec.TRIE_FILE_EXTENSION;
+        // TODO: pass the directory name instead
+        return "/" + FormatSpec.HEADER_FILE_EXTENSION;
     }
 
     public void addMultipleDictionaryEntriesToDictionary(
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/dictionary_structure_with_buffer_policy_factory.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/dictionary_structure_with_buffer_policy_factory.cpp
index f1b733a9c..dfb110cdd 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/dictionary_structure_with_buffer_policy_factory.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/dictionary_structure_with_buffer_policy_factory.cpp
@@ -47,7 +47,7 @@ namespace latinime {
         case FormatUtils::VERSION_4: {
             const int dictDirPathBufSize = strlen(path) + 1 /* terminator */;
             char dictDirPath[dictDirPathBufSize];
-            if (!FileUtils::getFilePathWithoutSuffix(path, Ver4DictConstants::TRIE_FILE_EXTENSION,
+            if (!FileUtils::getFilePathWithoutSuffix(path, Ver4DictConstants::HEADER_FILE_EXTENSION,
                     dictDirPathBufSize, dictDirPath)) {
                 // Dictionary file name is not valid as a version 4 dictionary.
                 return DictionaryStructureWithBufferPolicy::StructurePolicyPtr(0);
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/single_dict_content.h b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/single_dict_content.h
index bf833239b..9512bdbb0 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/single_dict_content.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/single_dict_content.h
@@ -60,9 +60,8 @@ class SingleDictContent : public DictContent {
     }
 
     bool flush(const char *const dictDirPath, const char *const contentFileName) const {
-        const BufferWithExtendableBuffer *bufferPtr = &mExpandableContentBuffer;
-        return DictFileWritingUtils::flushBuffersToFileInDir(dictDirPath, contentFileName,
-                &bufferPtr, 1 /* bufferCount */);
+        return DictFileWritingUtils::flushBufferToFileInDir(dictDirPath, contentFileName,
+                &mExpandableContentBuffer);
     }
 
  private:
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/sparse_table_dict_content.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/sparse_table_dict_content.cpp
index c65420614..84aceeffe 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/sparse_table_dict_content.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/sparse_table_dict_content.cpp
@@ -21,19 +21,16 @@ namespace latinime {
 bool SparseTableDictContent::flush(const char *const dictDirPath,
         const char *const lookupTableFileName, const char *const addressTableFileName,
         const char *const contentFileName) const {
-    const BufferWithExtendableBuffer *lookupTableBufferPtr = &mExpandableLookupTableBuffer;
-    if (!DictFileWritingUtils::flushBuffersToFileInDir(dictDirPath, lookupTableFileName,
-            &lookupTableBufferPtr, 1 /* bufferCount */)) {
+    if (!DictFileWritingUtils::flushBufferToFileInDir(dictDirPath, lookupTableFileName,
+            &mExpandableLookupTableBuffer)){
         return false;
     }
-    const BufferWithExtendableBuffer *addressTableBufferPtr = &mExpandableAddressTableBuffer;
-    if (!DictFileWritingUtils::flushBuffersToFileInDir(dictDirPath, addressTableFileName,
-            &addressTableBufferPtr, 1 /* bufferCount */)) {
+    if (!DictFileWritingUtils::flushBufferToFileInDir(dictDirPath, addressTableFileName,
+            &mExpandableAddressTableBuffer)) {
         return false;
     }
-    const BufferWithExtendableBuffer *contentBufferPtr = &mExpandableContentBuffer;
-    if (!DictFileWritingUtils::flushBuffersToFileInDir(dictDirPath, contentFileName,
-            &contentBufferPtr, 1 /* bufferCount */)) {
+    if (!DictFileWritingUtils::flushBufferToFileInDir(dictDirPath, contentFileName,
+            &mExpandableContentBuffer)) {
         return false;
     }
     return true;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.cpp
index d0853a5d3..24f62cd4b 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.cpp
@@ -28,7 +28,7 @@ int TerminalPositionLookupTable::getTerminalPtNodePosition(const int terminalId)
     const int terminalPos = getBuffer()->readUint(
             Ver4DictConstants::TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE, getEntryPos(terminalId));
     return (terminalPos == Ver4DictConstants::NOT_A_TERMINAL_ADDRESS) ?
-            NOT_A_DICT_POS : terminalPos - mHeaderRegionSize;
+            NOT_A_DICT_POS : terminalPos;
 }
 
 bool TerminalPositionLookupTable::setTerminalPtNodePosition(
@@ -45,18 +45,16 @@ bool TerminalPositionLookupTable::setTerminalPtNodePosition(
         mSize++;
     }
     const int terminalPos = (terminalPtNodePos != NOT_A_DICT_POS) ?
-            terminalPtNodePos + mHeaderRegionSize : Ver4DictConstants::NOT_A_TERMINAL_ADDRESS;
+            terminalPtNodePos : Ver4DictConstants::NOT_A_TERMINAL_ADDRESS;
     return getWritableBuffer()->writeUint(terminalPos,
             Ver4DictConstants::TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE, getEntryPos(terminalId));
 }
 
-bool TerminalPositionLookupTable::flushToFile(const char *const dictDirPath,
-        const int newHeaderRegionSize) const {
-    const int headerRegionSizeDiff = newHeaderRegionSize - mHeaderRegionSize;
-    // If header region size has been changed or used buffer size is smaller than actual buffer
-    // size, regenerate lookup table and write the new table to file.
-    if (headerRegionSizeDiff != 0 || getEntryPos(mSize) < getBuffer()->getTailPosition()) {
-        TerminalPositionLookupTable lookupTableToWrite(newHeaderRegionSize);
+bool TerminalPositionLookupTable::flushToFile(const char *const dictDirPath) const {
+    // If the used buffer size is smaller than the actual buffer size, regenerate the lookup
+    // table and write the new table to the file.
+    if (getEntryPos(mSize) < getBuffer()->getTailPosition()) {
+        TerminalPositionLookupTable lookupTableToWrite;
         for (int i = 0; i < mSize; ++i) {
             const int terminalPtNodePosition = getTerminalPtNodePosition(i);
             if (!lookupTableToWrite.setTerminalPtNodePosition(i, terminalPtNodePosition)) {
@@ -68,7 +66,7 @@ bool TerminalPositionLookupTable::flushToFile(const char *const dictDirPath,
         return lookupTableToWrite.flush(dictDirPath,
                 Ver4DictConstants::TERMINAL_ADDRESS_TABLE_FILE_EXTENSION);
     } else {
-        // We can simply use this lookup table because the header region size has not been
+        // We can simply use this lookup table because the buffer size has not been
         // changed.
         return flush(dictDirPath, Ver4DictConstants::TERMINAL_ADDRESS_TABLE_FILE_EXTENSION);
     }
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.h b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.h
index 80b358c43..283b40237 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.h
@@ -28,19 +28,13 @@ class TerminalPositionLookupTable : public SingleDictContent {
  public:
     typedef hash_map_compat<int, int> TerminalIdMap;
 
-    // TODO: Quit using headerRegionSize.
-    TerminalPositionLookupTable(const char *const dictDirPath, const bool isUpdatable,
-            const int headerRegionSize)
+    TerminalPositionLookupTable(const char *const dictDirPath, const bool isUpdatable)
             : SingleDictContent(dictDirPath,
                       Ver4DictConstants::TERMINAL_ADDRESS_TABLE_FILE_EXTENSION, isUpdatable),
               mSize(getBuffer()->getTailPosition()
-                      / Ver4DictConstants::TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE),
-              mHeaderRegionSize(headerRegionSize) {}
+                      / Ver4DictConstants::TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE) {}
 
-    explicit TerminalPositionLookupTable(const int headerRegionSize)
-            : mSize(0), mHeaderRegionSize(headerRegionSize) {}
-
-    TerminalPositionLookupTable() : mSize(0), mHeaderRegionSize(0) {}
+    TerminalPositionLookupTable() : mSize(0) {}
 
     int getTerminalPtNodePosition(const int terminalId) const;
 
@@ -50,7 +44,7 @@ class TerminalPositionLookupTable : public SingleDictContent {
         return mSize;
     }
 
-    bool flushToFile(const char *const dictDirPath, const int newHeaderRegionSize) const;
+    bool flushToFile(const char *const dictDirPath) const;
 
     bool runGCTerminalIds(TerminalIdMap *const terminalIdMap);
 
@@ -62,7 +56,6 @@ class TerminalPositionLookupTable : public SingleDictContent {
     }
 
     int mSize;
-    const int mHeaderRegionSize;
 };
 } // namespace latinime
 #endif // LATINIME_TERMINAL_POSITION_LOOKUP_TABLE_H
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.cpp
index 40c9b5e78..10f8d32e7 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.cpp
@@ -45,16 +45,22 @@ bool Ver4DictBuffers::flushHeaderAndDictBuffers(const char *const dictDirPath,
         AKLOGE("Cannot create directory: %s. errno: %d.", tmpDirPath, errno);
         return false;
     }
+    // Write header file.
+    if (!DictFileWritingUtils::flushBufferToFileInDir(tmpDirPath,
+            Ver4DictConstants::HEADER_FILE_EXTENSION, headerBuffer)) {
+        AKLOGE("Dictionary header file %s/%s cannot be written.", tmpDirPath,
+                Ver4DictConstants::HEADER_FILE_EXTENSION);
+        return false;
+    }
     // Write trie file.
-    const BufferWithExtendableBuffer *buffers[] = {headerBuffer, &mExpandableTrieBuffer};
-    if (!DictFileWritingUtils::flushBuffersToFileInDir(tmpDirPath,
-            Ver4DictConstants::TRIE_FILE_EXTENSION, buffers, 2 /* bufferCount */)) {
+    if (!DictFileWritingUtils::flushBufferToFileInDir(tmpDirPath,
+            Ver4DictConstants::TRIE_FILE_EXTENSION, &mExpandableTrieBuffer)) {
         AKLOGE("Dictionary trie file %s/%s cannot be written.", tmpDirPath,
                 Ver4DictConstants::TRIE_FILE_EXTENSION);
         return false;
     }
     // Write dictionary contents.
-    if (!mTerminalPositionLookupTable.flushToFile(tmpDirPath, headerBuffer->getTailPosition())) {
+    if (!mTerminalPositionLookupTable.flushToFile(tmpDirPath)) {
         AKLOGE("Terminal position lookup table cannot be written. %s", tmpDirPath);
         return false;
     }
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.h b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.h
index 153d8990a..8a13671c0 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.h
@@ -34,9 +34,10 @@ class Ver4DictBuffers {
     typedef ExclusiveOwnershipPointer<Ver4DictBuffers> Ver4DictBuffersPtr;
 
     static AK_FORCE_INLINE Ver4DictBuffersPtr openVer4DictBuffers(const char *const dictDirPath,
-            const MmappedBuffer::MmappedBufferPtr &dictBuffer) {
-        const bool isUpdatable = dictBuffer.get() ? dictBuffer.get()->isUpdatable() : false;
-        return Ver4DictBuffersPtr(new Ver4DictBuffers(dictDirPath, dictBuffer, isUpdatable));
+            const MmappedBuffer::MmappedBufferPtr &headerBuffer) {
+        const bool isUpdatable = headerBuffer.get() ? headerBuffer.get()->isUpdatable() : false;
+        // TODO: take only dictDirPath, and open both header and trie files in the constructor below
+        return Ver4DictBuffersPtr(new Ver4DictBuffers(dictDirPath, headerBuffer, isUpdatable));
     }
 
     static AK_FORCE_INLINE Ver4DictBuffersPtr createVer4DictBuffers(
@@ -121,16 +122,17 @@ class Ver4DictBuffers {
     DISALLOW_COPY_AND_ASSIGN(Ver4DictBuffers);
 
     AK_FORCE_INLINE Ver4DictBuffers(const char *const dictDirPath,
-            const MmappedBuffer::MmappedBufferPtr &dictBuffer, const bool isUpdatable)
-            : mDictBuffer(dictBuffer),
-              mHeaderPolicy(mDictBuffer.get()->getBuffer(), FormatUtils::VERSION_4),
-              mExpandableHeaderBuffer(dictBuffer.get()->getBuffer(), mHeaderPolicy.getSize(),
+            const MmappedBuffer::MmappedBufferPtr &headerBuffer, const bool isUpdatable)
+            : mHeaderBuffer(headerBuffer),
+              mDictBuffer(MmappedBuffer::openBuffer(dictDirPath,
+                      Ver4DictConstants::TRIE_FILE_EXTENSION, isUpdatable)),
+              mHeaderPolicy(headerBuffer.get()->getBuffer(), FormatUtils::VERSION_4),
+              mExpandableHeaderBuffer(headerBuffer.get()->getBuffer(), mHeaderPolicy.getSize(),
                       BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE),
-              mExpandableTrieBuffer(dictBuffer.get()->getBuffer() + mHeaderPolicy.getSize(),
-                      dictBuffer.get()->getBufferSize() - mHeaderPolicy.getSize(),
+              mExpandableTrieBuffer(mDictBuffer.get()->getBuffer(),
+                      mDictBuffer.get()->getBufferSize(),
                       BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE),
-              // TODO: Quit using header size.
-              mTerminalPositionLookupTable(dictDirPath, isUpdatable, mHeaderPolicy.getSize()),
+              mTerminalPositionLookupTable(dictDirPath, isUpdatable),
               mProbabilityDictContent(dictDirPath, mHeaderPolicy.hasHistoricalInfoOfWords(),
                       isUpdatable),
               mBigramDictContent(dictDirPath, mHeaderPolicy.hasHistoricalInfoOfWords(),
@@ -139,7 +141,7 @@ class Ver4DictBuffers {
               mIsUpdatable(isUpdatable) {}
 
     AK_FORCE_INLINE Ver4DictBuffers(const HeaderPolicy *const headerPolicy)
-            : mDictBuffer(0), mHeaderPolicy(),
+            : mHeaderBuffer(0), mDictBuffer(0), mHeaderPolicy(),
               mExpandableHeaderBuffer(Ver4DictConstants::MAX_DICTIONARY_SIZE),
               mExpandableTrieBuffer(Ver4DictConstants::MAX_DICTIONARY_SIZE),
               mTerminalPositionLookupTable(),
@@ -147,6 +149,7 @@ class Ver4DictBuffers {
               mBigramDictContent(headerPolicy->hasHistoricalInfoOfWords()), mShortcutDictContent(),
               mIsUpdatable(true) {}
 
+    const MmappedBuffer::MmappedBufferPtr mHeaderBuffer;
     const MmappedBuffer::MmappedBufferPtr mDictBuffer;
     const HeaderPolicy mHeaderPolicy;
     BufferWithExtendableBuffer mExpandableHeaderBuffer;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.cpp
index 066d6ed80..34fecc25f 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.cpp
@@ -18,7 +18,9 @@
 
 namespace latinime {
 
+// These values MUST match the definitions in FormatSpec.java.
 const char *const Ver4DictConstants::TRIE_FILE_EXTENSION = ".trie";
+const char *const Ver4DictConstants::HEADER_FILE_EXTENSION = ".header";
 const char *const Ver4DictConstants::FREQ_FILE_EXTENSION = ".freq";
 // tat = Terminal Address Table
 const char *const Ver4DictConstants::TERMINAL_ADDRESS_TABLE_FILE_EXTENSION = ".tat";
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h
index 7afdc86ed..c16e0bdcb 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h
@@ -25,6 +25,7 @@ namespace latinime {
 class Ver4DictConstants {
  public:
     static const char *const TRIE_FILE_EXTENSION;
+    static const char *const HEADER_FILE_EXTENSION;
     static const char *const FREQ_FILE_EXTENSION;
     static const char *const TERMINAL_ADDRESS_TABLE_FILE_EXTENSION;
     static const char *const BIGRAM_FILE_EXTENSION;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/dict_file_writing_utils.cpp b/native/jni/src/suggest/policyimpl/dictionary/utils/dict_file_writing_utils.cpp
index b463d4149..9223356c1 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/dict_file_writing_utils.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/utils/dict_file_writing_utils.cpp
@@ -68,42 +68,43 @@ const char *const DictFileWritingUtils::TEMP_FILE_SUFFIX_FOR_WRITING_DICT_FILE =
     char tmpFileName[tmpFileNameBufSize];
     FileUtils::getFilePathWithSuffix(filePath, TEMP_FILE_SUFFIX_FOR_WRITING_DICT_FILE,
             tmpFileNameBufSize, tmpFileName);
-    const BufferWithExtendableBuffer *buffers[] = {dictHeader, dictBody};
-    if (!DictFileWritingUtils::flushBuffersToFile(tmpFileName, buffers, 2 /* bufferCount */)) {
+    if (!DictFileWritingUtils::flushBufferToFile(tmpFileName, dictHeader)) {
+        AKLOGE("Dictionary header cannot be written to %s.", tmpFileName);
+        return false;
+    }
+    if (!DictFileWritingUtils::flushBufferToFile(tmpFileName, dictBody)) {
         AKLOGE("Dictionary structure cannot be written to %s.", tmpFileName);
         return false;
     }
     if (rename(tmpFileName, filePath) != 0) {
         AKLOGE("Dictionary file %s cannot be renamed to %s", tmpFileName, filePath);;
+        return false;
     }
     return true;
 }
 
-/* static */ bool DictFileWritingUtils::flushBuffersToFileInDir(const char *const dirPath,
-        const char *const fileName, const BufferWithExtendableBuffer **const buffers,
-        const int bufferCount) {
+/* static */ bool DictFileWritingUtils::flushBufferToFileInDir(const char *const dirPath,
+        const char *const fileName, const BufferWithExtendableBuffer *const buffer) {
     const int filePathBufSize = FileUtils::getFilePathBufSize(dirPath, fileName);
     char filePath[filePathBufSize];
     FileUtils::getFilePath(dirPath, fileName, filePathBufSize, filePath);
-    return flushBuffersToFile(filePath, buffers, bufferCount);
+    return flushBufferToFile(filePath, buffer);
 }
 
-/* static */ bool DictFileWritingUtils::flushBuffersToFile(const char *const filePath,
-        const BufferWithExtendableBuffer **const buffers, const int bufferCount) {
+/* static */ bool DictFileWritingUtils::flushBufferToFile(const char *const filePath,
+        const BufferWithExtendableBuffer *const buffer) {
     FILE *const file = fopen(filePath, "wb");
     if (!file) {
         AKLOGE("File %s cannot be opened.", filePath);
         ASSERT(false);
         return false;
     }
-    for (int i = 0; i < bufferCount; ++i) {
-        if (!writeBufferToFile(file, buffers[i])) {
-            remove(filePath);
-            AKLOGE("Buffer cannot be written to the file %s. size: %d", filePath,
-                    buffers[i]->getTailPosition());
-            ASSERT(false);
-            return false;
-        }
+    if (!writeBufferToFile(file, buffer)) {
+        remove(filePath);
+        AKLOGE("Buffer cannot be written to the file %s. size: %d", filePath,
+                buffer->getTailPosition());
+        ASSERT(false);
+        return false;
     }
     fclose(file);
     return true;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h b/native/jni/src/suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h
index 612d75445..ffd9db623 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h
@@ -37,8 +37,8 @@ class DictFileWritingUtils {
             BufferWithExtendableBuffer *const dictHeader,
             BufferWithExtendableBuffer *const dictBody);
 
-    static bool flushBuffersToFileInDir(const char *const dirPath, const char *const fileName,
-            const BufferWithExtendableBuffer **const buffers, const int bufferCount);
+    static bool flushBufferToFileInDir(const char *const dirPath, const char *const fileName,
+            const BufferWithExtendableBuffer *const buffer);
 
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(DictFileWritingUtils);
@@ -46,8 +46,8 @@ class DictFileWritingUtils {
     static bool createEmptyV4DictFile(const char *const filePath,
             const HeaderReadWriteUtils::AttributeMap *const attributeMap);
 
-    static bool flushBuffersToFile(const char *const filePath,
-            const BufferWithExtendableBuffer **const buffers, const int bufferCount);
+    static bool flushBufferToFile(const char *const filePath,
+            const BufferWithExtendableBuffer *const buffer);
 
     static bool writeBufferToFile(FILE *const file,
             const BufferWithExtendableBuffer *const buffer);
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/format_utils.h b/native/jni/src/suggest/policyimpl/dictionary/utils/format_utils.h
index 3d14d2607..34727b8d8 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/format_utils.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/utils/format_utils.h
@@ -29,9 +29,10 @@ namespace latinime {
 class FormatUtils {
  public:
     enum FORMAT_VERSION {
+        // These MUST have the same values as the relevant constants in FormatSpec.java.
         VERSION_2 = 2,
         VERSION_3 = 3,
-        VERSION_4 = 4,
+        VERSION_4 = 400,
         UNKNOWN_VERSION = -1
     };
 
diff --git a/tests/src/com/android/inputmethod/latin/BinaryDictionaryDecayingTests.java b/tests/src/com/android/inputmethod/latin/BinaryDictionaryDecayingTests.java
index c63193aeb..61b391a2d 100644
--- a/tests/src/com/android/inputmethod/latin/BinaryDictionaryDecayingTests.java
+++ b/tests/src/com/android/inputmethod/latin/BinaryDictionaryDecayingTests.java
@@ -22,6 +22,7 @@ import android.util.Pair;
 
 import com.android.inputmethod.latin.makedict.CodePointUtils;
 import com.android.inputmethod.latin.makedict.FormatSpec;
+import com.android.inputmethod.latin.utils.FileUtils;
 
 import java.io.File;
 import java.io.IOException;
@@ -102,7 +103,7 @@ public class BinaryDictionaryDecayingTests extends AndroidTestCase {
 
     private File createEmptyDictionaryAndGetFile(final String dictId,
             final int formatVersion) throws IOException {
-        if (formatVersion == 4) {
+        if (formatVersion == FormatSpec.VERSION4) {
             return createEmptyVer4DictionaryAndGetFile(dictId);
         } else {
             throw new IOException("Dictionary format version " + formatVersion
@@ -112,7 +113,7 @@ public class BinaryDictionaryDecayingTests extends AndroidTestCase {
     private File createEmptyVer4DictionaryAndGetFile(final String dictId) throws IOException {
         final File file = File.createTempFile(dictId, TEST_DICT_FILE_EXTENSION,
                 getContext().getCacheDir());
-        file.delete();
+        FileUtils.deleteRecursively(file);
         file.mkdir();
         Map<String, String> attributeMap = new HashMap<String, String>();
         attributeMap.put(FormatSpec.FileHeader.SUPPORTS_DYNAMIC_UPDATE_ATTRIBUTE,
@@ -123,10 +124,10 @@ public class BinaryDictionaryDecayingTests extends AndroidTestCase {
                 FormatSpec.FileHeader.ATTRIBUTE_VALUE_TRUE);
         if (BinaryDictionary.createEmptyDictFile(file.getAbsolutePath(),
                 FormatSpec.VERSION4, attributeMap)) {
-            return new File(file, FormatSpec.TRIE_FILE_EXTENSION);
+            return new File(file, FormatSpec.HEADER_FILE_EXTENSION);
         } else {
             throw new IOException("Empty dictionary " + file.getAbsolutePath() + " "
-                    + FormatSpec.TRIE_FILE_EXTENSION + " cannot be created.");
+                    + FormatSpec.HEADER_FILE_EXTENSION + " cannot be created.");
         }
     }
 
diff --git a/tests/src/com/android/inputmethod/latin/BinaryDictionaryTests.java b/tests/src/com/android/inputmethod/latin/BinaryDictionaryTests.java
index 7fa52e902..c14840258 100644
--- a/tests/src/com/android/inputmethod/latin/BinaryDictionaryTests.java
+++ b/tests/src/com/android/inputmethod/latin/BinaryDictionaryTests.java
@@ -72,10 +72,10 @@ public class BinaryDictionaryTests extends AndroidTestCase {
                 FormatSpec.FileHeader.ATTRIBUTE_VALUE_TRUE);
         if (BinaryDictionary.createEmptyDictFile(file.getAbsolutePath(),
                 FormatSpec.VERSION4, attributeMap)) {
-            return new File(file, FormatSpec.TRIE_FILE_EXTENSION);
+            return new File(file, FormatSpec.HEADER_FILE_EXTENSION);
         } else {
             throw new IOException("Empty dictionary " + file.getAbsolutePath() + " "
-                    + FormatSpec.TRIE_FILE_EXTENSION + " cannot be created.");
+                    + FormatSpec.HEADER_FILE_EXTENSION + " cannot be created.");
         }
     }
 
diff --git a/tests/src/com/android/inputmethod/latin/makedict/BinaryDictDecoderEncoderTests.java b/tests/src/com/android/inputmethod/latin/makedict/BinaryDictDecoderEncoderTests.java
index 05de37d4c..e3ec2eca9 100644
--- a/tests/src/com/android/inputmethod/latin/makedict/BinaryDictDecoderEncoderTests.java
+++ b/tests/src/com/android/inputmethod/latin/makedict/BinaryDictDecoderEncoderTests.java
@@ -523,7 +523,7 @@ public class BinaryDictDecoderEncoderTests extends AndroidTestCase {
             return null;
         }
         if (fileHeader == null) return null;
-        return BinaryDictDecoderUtils.getWordAtPosition(dictDecoder, fileHeader.mHeaderSize,
+        return BinaryDictDecoderUtils.getWordAtPosition(dictDecoder, fileHeader.mBodyOffset,
                 address, fileHeader.mFormatOptions).mWord;
     }
 
diff --git a/tests/src/com/android/inputmethod/latin/makedict/BinaryDictIOUtilsTests.java b/tests/src/com/android/inputmethod/latin/makedict/BinaryDictIOUtilsTests.java
index da217cea6..308919499 100644
--- a/tests/src/com/android/inputmethod/latin/makedict/BinaryDictIOUtilsTests.java
+++ b/tests/src/com/android/inputmethod/latin/makedict/BinaryDictIOUtilsTests.java
@@ -216,7 +216,7 @@ public class BinaryDictIOUtilsTests extends AndroidTestCase {
             final DictDecoder dictDecoder = FormatSpec.getDictDecoder(file);
             final FileHeader fileHeader = dictDecoder.readHeader();
             assertEquals(word,
-                    BinaryDictDecoderUtils.getWordAtPosition(dictDecoder, fileHeader.mHeaderSize,
+                    BinaryDictDecoderUtils.getWordAtPosition(dictDecoder, fileHeader.mBodyOffset,
                             position, fileHeader.mFormatOptions).mWord);
         } catch (IOException e) {
             Log.e(TAG, "Raised an IOException while looking up a word", e);
diff --git a/tests/src/com/android/inputmethod/latin/makedict/BinaryDictUtils.java b/tests/src/com/android/inputmethod/latin/makedict/BinaryDictUtils.java
index 8b1521a6c..ad17a7118 100644
--- a/tests/src/com/android/inputmethod/latin/makedict/BinaryDictUtils.java
+++ b/tests/src/com/android/inputmethod/latin/makedict/BinaryDictUtils.java
@@ -29,17 +29,18 @@ public class BinaryDictUtils {
 
     public static final String TEST_DICT_FILE_EXTENSION = ".testDict";
 
-    public static final FormatSpec.FormatOptions VERSION2 = new FormatSpec.FormatOptions(2);
+    public static final FormatSpec.FormatOptions VERSION2 =
+            new FormatSpec.FormatOptions(FormatSpec.VERSION2);
     public static final FormatSpec.FormatOptions VERSION3_WITHOUT_DYNAMIC_UPDATE =
-            new FormatSpec.FormatOptions(3, false /* supportsDynamicUpdate */);
+            new FormatSpec.FormatOptions(FormatSpec.VERSION3, false /* supportsDynamicUpdate */);
     public static final FormatSpec.FormatOptions VERSION3_WITH_DYNAMIC_UPDATE =
-            new FormatSpec.FormatOptions(3, true /* supportsDynamicUpdate */);
+            new FormatSpec.FormatOptions(FormatSpec.VERSION3, true /* supportsDynamicUpdate */);
     public static final FormatSpec.FormatOptions VERSION4_WITHOUT_DYNAMIC_UPDATE =
-            new FormatSpec.FormatOptions(4, false /* supportsDynamicUpdate */);
+            new FormatSpec.FormatOptions(FormatSpec.VERSION4, false /* supportsDynamicUpdate */);
     public static final FormatSpec.FormatOptions VERSION4_WITH_DYNAMIC_UPDATE =
-            new FormatSpec.FormatOptions(4, true /* supportsDynamicUpdate */);
+            new FormatSpec.FormatOptions(FormatSpec.VERSION4, true /* supportsDynamicUpdate */);
     public static final FormatSpec.FormatOptions VERSION4_WITH_DYNAMIC_UPDATE_AND_TIMESTAMP =
-            new FormatSpec.FormatOptions(4, true /* supportsDynamicUpdate */,
+            new FormatSpec.FormatOptions(FormatSpec.VERSION4, true /* supportsDynamicUpdate */,
                     true /* hasTimestamp */);
 
     public static DictionaryOptions makeDictionaryOptions(final String id, final String version) {
@@ -53,9 +54,10 @@ public class BinaryDictUtils {
 
     public static File getDictFile(final String name, final String version,
             final FormatOptions formatOptions, final File directory) {
-        if (formatOptions.mVersion == 2 || formatOptions.mVersion == 3) {
+        if (formatOptions.mVersion == FormatSpec.VERSION2
+                || formatOptions.mVersion == FormatSpec.VERSION3) {
             return new File(directory, name + "." + version + TEST_DICT_FILE_EXTENSION);
-        } else if (formatOptions.mVersion == 4) {
+        } else if (formatOptions.mVersion == FormatSpec.VERSION4) {
             return new File(directory, name + "." + version);
         } else {
             throw new RuntimeException("the format option has a wrong version : "
@@ -67,7 +69,8 @@ public class BinaryDictUtils {
             final File cacheDir) {
         if (formatOptions.mVersion == FormatSpec.VERSION4) {
             return new Ver4DictEncoder(cacheDir);
-        } else if (formatOptions.mVersion == 3 || formatOptions.mVersion == 2) {
+        } else if (formatOptions.mVersion == FormatSpec.VERSION3
+                || formatOptions.mVersion == FormatSpec.VERSION2) {
             return new Ver3DictEncoder(file);
         } else {
             throw new RuntimeException("The format option has a wrong version : "
@@ -79,7 +82,7 @@ public class BinaryDictUtils {
             throws UnsupportedFormatException {
         if (formatOptions.mVersion == FormatSpec.VERSION4) {
             return new Ver4DictUpdater(file, DictDecoder.USE_WRITABLE_BYTEBUFFER);
-        } else if (formatOptions.mVersion == 3) {
+        } else if (formatOptions.mVersion == FormatSpec.VERSION3) {
             return new Ver3DictUpdater(file, DictDecoder.USE_WRITABLE_BYTEBUFFER);
         } else {
             throw new UnsupportedFormatException("The format option has a wrong version : "
diff --git a/tools/dicttool/Android.mk b/tools/dicttool/Android.mk
index 3d09c0508..895e4a231 100644
--- a/tools/dicttool/Android.mk
+++ b/tools/dicttool/Android.mk
@@ -30,6 +30,7 @@ MAKEDICT_CORE_SOURCE_DIRECTORY := $(LATINIME_CORE_SOURCE_DIRECTORY)/makedict
 USED_TARGETTED_UTILS := \
         $(LATINIME_CORE_SOURCE_DIRECTORY)/utils/ByteArrayDictBuffer.java \
         $(LATINIME_CORE_SOURCE_DIRECTORY)/utils/CollectionUtils.java \
+        $(LATINIME_CORE_SOURCE_DIRECTORY)/utils/FileUtils.java \
         $(LATINIME_CORE_SOURCE_DIRECTORY)/utils/JniUtils.java
 
 DICTTOOL_ONDEVICE_TESTS_DIRECTORY := \
diff --git a/tools/dicttool/src/com/android/inputmethod/latin/dicttool/DictionaryMaker.java b/tools/dicttool/src/com/android/inputmethod/latin/dicttool/DictionaryMaker.java
index 5c7e8b4f2..b3543a0c2 100644
--- a/tools/dicttool/src/com/android/inputmethod/latin/dicttool/DictionaryMaker.java
+++ b/tools/dicttool/src/com/android/inputmethod/latin/dicttool/DictionaryMaker.java
@@ -159,9 +159,9 @@ public class DictionaryMaker {
                     if (OPTION_VERSION_2.equals(arg)) {
                         // Do nothing, this is the default
                     } else if (OPTION_VERSION_3.equals(arg)) {
-                        outputBinaryFormatVersion = 3;
+                        outputBinaryFormatVersion = FormatSpec.VERSION3;
                     } else if (OPTION_VERSION_4.equals(arg)) {
-                        outputBinaryFormatVersion = 4;
+                        outputBinaryFormatVersion = FormatSpec.VERSION4;
                     } else if (OPTION_HELP.equals(arg)) {
                         displayHelp();
                     } else {
@@ -358,7 +358,7 @@ public class DictionaryMaker {
         final File outputFile = new File(outputFilename);
         final FormatSpec.FormatOptions formatOptions = new FormatSpec.FormatOptions(version);
         final DictEncoder dictEncoder;
-        if (version == 4) {
+        if (version == FormatSpec.VERSION4) {
             dictEncoder = new Ver4DictEncoder(outputFile);
         } else {
             dictEncoder = new Ver3DictEncoder(outputFile);